Electric furnace.



J. BURKE.

ELECTRIC FURNACE.

APPLICATION FILED mo. 10, 1910.

1,082,459. Patented Dec. 23, 1913.

To all whom it may concern t TED STATES PATENT orr on.

JAMES BURKE, OF PENNSYLVANIA, ASSIGNOB 1'0 BURKE ELECTRIC COMPANY, ACORPORATION OF PENNSYLVANIA.

I ELECTRIC FURNACE.

Be it known that I, JAMES BURKE, critizen of the United States, residingat Erie, m the county of Erie and State of Pennsylvania, have inventedcertain new and useful Improvements in Electric Furnaces, of which thefollowing is a full, clear, and exact specification.

This invention relates to a construction and arrangement embodying anelectric furnace and energy-supplying means, and to the method ofoperating the same.

More specifically, this invention relates to an arrangement andconstruction embodying a source of polyphase currents, such as atransformer, or the like, and an electric furnace in which the severalphases constituting the polyphase currents are separately utilized toeffect heating or electrolysis.

My invention contemplates further the method of leading the severalcurrents gen erated by a polyphase transformer, or the like, to distinctelectrodes of an electric furnace where the full energy of each phase isavailable in the interior of the furnace.

It has been heretofore proposed to employ polyphase currents forsupplying energy to the electrodes of an electric furnace; however, suchprior organizations of a source of polyphase currents and an electricfurnace have entailed arran ements in which the full energy of the polypase currents is not ut-ili ized to the best advantage in the furnace, Insuch prior constructions the several phases of the polyphase currentsare combined before reaching the interior of the furnace so that anelectrode is supplied with a current which is the resultant of two ormore phases, which resultant has a watt value which is less than thearithmetical sum of the watt values of the component currents. Accordingto my invention, the separate phases of polyphase currents generated bythe transformer, or the like, are led by distinct paths to the interiorof the furnace in such manner that the full energy of each phase isavailable to effect reactions in heat and electrolysis.

My invention may be described in one form as applied to an electricfurnace of the arc type, the electrodes of which are individuallyconnected to the mains supplying the polyphase currents, that is, to theconductors leading from the secondary coils of the transformer or thelike. In the pre- Specmcaflon of Letters Intent.

Application filed December 10, 1810. Serial Ila. 696,732.

Patented Dec. 23, 1913.

ferred forms of my invention, the number of electrodes is chosen astwice the number of separate phases of polyphase currents, eachelectrode being disposed so that an arc will be formed between the sameand the charge to be treated in the furnace. In such preferred forms,each end of the secondary coil or coils is supplied with a separateterminal, so that the several phases generated in the windings of therespective secondaries are individually) led to the electrodes of thefurthree-phase currents from a transformer in accordance with myinvention.

The transformer 1 .having primary coils 2, 3, 4, is shown connected tothe mains 5, 6, 7 in star connection; however, the delta connection orany other form of connection may be employed, as will be readilyunderstood. The secondary coils 8, 9, 10 are disposed in proper relationto the primary coils 2, 3, 4, respectively, to convert the severalphases of currents to the desired voltage, as will be understood. Saidseconda coils are provided with distinct terminals, designated in pairsas 11 and 12, 13 and 14, and 15 and 16, said terminals being connectedto the pairs of leads 17 and .18, 19 and 20, and 21 and 22,respectively.

The furnace 23 is provided with six electrodes 24, 25, 26, 27, 28 and29, electrically connected with the respective leads 17, 18, 19, 20, 21and 22. Said electrodes 24 to 29 are supported in any approved manner,as at their upper ends and projecting into the body of the electricfurnace. The specific details as to feeding the electrodes into theinterior of the furnace will be determined by certain conditions, aswill be understood. The electrodes and any other parts or portions ofthe furnace may be rovided with coolin means of any ap roveconstruction. The character of the e arge and the purposes for which thecharge is treated, will determine the construction and arrangement ofthe parts of the furnace, as well as the nature of the lining of thefurnace parts.

It will be noted that I have grouped the electrodes in the specific formshown in the figure, so that the electrode 24: connected to lead 17 isclosely disposed to electrode 29 connected to lead 22; similarly, theremaining electrodes are so related that those electrodes connected tothe adjacent terminals of the secondary coils are positioned in closeproximity to each other. The arrangement shown in the figure is highlyadvantageous, but it will be seen that the electrodes may be grouped inthe interior of the furnace in any desired order or series, since thereis at all instants a difference of potential between any electrode andthe charge or portion of the charge.

I wish it to be understood that my method may be carried out by means ofthree singlephase transformers connected to the respective three-phaseconductors, as well as by a unitary three-phase transformer. It willalso be understood that the number of phases of the secondary circuitneed not necessarily be the same as that of the phases of the primarycircuit, since my invention may. be carried out in any alternatingcurrent-supplying system, in which two or more phases are obtained inthe transformer or groups of transformers.

Specific reference has been made to threephase currents, but suchreference has been made for the purpose of describing my invention as tocertain specific forms thereof which are particularly advantageous atthe present time owing to the prevailing use of three-phase currents forlong distance transmission. I have found that by reason of myarrangement and my method of operating there results an increase ofseventeen or more per cent. in energy available in the interior of thefurnace when employing threephase currents, thus effecting a materialincrease. In like manner, two, four, six, and other polyphase currentsmay be utilized to effect my invention.

Having thus described my invention, I declare that what I claim as newand desire to secure by Letters Patent, is-

1. The combination of a polyphase transforming device having secondarycoils unconnected with one another, conductors running from theterminals of said secondary coils and an electric furnace havingelectrodes connected to said conductors.

2. The combination of a three-phase -transf0rming device, the secondarycolls of which are unconnected with one another, conductors connected tothe terminals of said secondary (3011s, and an electric furnace phases,

having electrodes connected to said conductors.

3. The method of energizing a furnace with polyphase electric currents,comprising transforming alternatin current to produce a plurality ofsecon ary alternating currents of different phases, and leading saidphases of alternatin current independently to pairs of electro es ofsaid furnace.

4. The method 'of supplying a furnace with polyphase electrical energy,comprising producin a plurality of alternatin currents of itferent phaserelation, an leading said alternating currents independently to pairs ofelectrodes of said furnace. 75

5. In combination with an electric are i furnace, a polyphasetransforming device having secondary coils unconnected with one another,and electrodes disposed in said furnace in arcing relation with thecharge and connected to the terminals of said unconnected secondarycoils.

6. In combination with an electric furnace, a source of polyphasealternating currents, means for transforming said currents into distinctalternating currents of different and means for leading said phasesindependently to pairs of electrodes'of said furnace.

7. The combination of a source of polyphase currents, a polyphasetransformer having its secondary coils unconnected with one another,conductors running from the terminals of said secondary coils, andelectrodes in arcing relation with the charge in the furnace andconnected individually to said conductors.

8. The combination of an electric furnace, a sourceof three-phasecurrents, a threephase transforming device, the secondary coils of whichare unconnected with one another, conductors running from the terminalsof said secondary coils, and electrodes disposed in said furnace anddivided into sets, said sets being connected to said conductors.

9. The combination of a source of polyphase currents, av transformingdevice having at least two secondary windings electrically unconnectedwith one another, conductors connected to the terminals of saidsecondary windings, and at least two sets of electrodes disposed in saidfurnace and connected to said conductors.

In testimony whereof I afiix my signature, in presence of two witnesses.

JAMES BURKE.

Witnesses HENRY J. LUoKE, Gno. N. KERR.

